1. Field of the Invention
The present invention relates to a measuring device including a composite optical part in which a plurality of optical parts for guiding light rays to each of a plurality of photoelectric converters are integrated.
2. Description of the Related Art
Recently, with improvement in performance of cameras and reduction in the size thereof, various measuring devices such as rangefinding devices and photometric devices installed in cameras have also been reduced in size. For example, as shown in FIG. 3, the reduction in size is realized by mounting two photoelectric converters with different functions on the same semiconductor chip. In FIG. 3, reference numeral 1 designates a casing holding the entire device, 2 designates a semiconductor chip, 3 designates a photometric sensor comprised of a photoelectric converter, 4 designates a rangefinding sensor comprised of a photoelectric converter, 5 designates a photometric lens for guiding light rays to the photometric sensor 3, and 6 designates a rangefinding lens for guiding light rays to the rangefinding sensor 4. The photometric lens 5 and rangefinding lens 6 have collars 5a and 6a for holding and fixing the lenses to the casing 1, respectively, and the collars 5a and 6a are adhesively fixed to a holding portion 1a of the casing 1. Reference numeral 7 designates a typical optical path of light rays guided to the photometric sensor 3 by the photometric lens 5, and reference numeral 8 designates a typical optical path of light rays guided to the rangefinding sensor 4 by the rangefinding lens 6. The casing 1 is provided with a wall portion 1b for preventing undesired light rays from reaching each of the sensors in order to prevent a lowering in measuring accuracy due to undesired light rays being received by the sensors. However, as can be understood from FIG. 3, a space for the holding portion 1a for holding and fixing each lens to the casing 1 is necessary, and accordingly the entire device becomes large in size.
In a photometric device disclosed in Japanese Laid-Open Patent Publication (Kokai) No. H05-158107, photometry is carried out by providing a photoelectric converter between a pair of line sensors provided on the same semiconductor chip to be used for passive rangefinding, whereby the rangefinding device and the photometric device are integrated to realize reduction in size. However, since a total of three lenses including a pair of lenses for rangefinding and a lens for photometry are arranged horizontally and held and fixed to the casing, the entire device becomes large in size by the space for holding and fixing the lenses to the casing, as is the case with the measuring device of FIG. 3.
As a method for solving the abovementioned problem, a proposal has been made for reducing the space for holding and fixing the photometric lenses and the rangefinding lens to the casing by integrating the photometric lenses and the rangefinding lense, as shown in FIG. 4. In FIG. 4, reference numeral 9 designates an integrated lens which is comprised of a photometric lens portion 9a for guiding light rays to the photometric sensor 3 and a rangefinding lens portion 9b for guiding light rays to the rangefinding sensor 4, and has collars 9c for holding and fixing the integrated lens to the casing 1. By thus integrating the photometric lens 5 and the rangefinding lens 6 of FIG. 3 to form the integrated lens 9, the collars 5a and 6a that have been provided inside the photometric lens 5 and the rangefinding lens 6 are omitted, the corresponding holding portion 1a of the casing 1 becomes unnecessary, and accordingly the entire device becomes smaller in size.
However, since the lenses are integrated, it becomes inevitable that the wall portion 1b that has been provided between the photometric lens 5 and the rangefinding lens 6 in FIG. 3 extends only up to a position at which no interference with the integrated lens 9 occurs. Therefore, an optical path 10 is formed through which light rays from the outside of ranges to be measured enters from the photometric lens portion 9a, passes through the integrated portion, and exits from the rangefinding lens 9b and reaches the rangefinding sensor 4. As a result, the rangefinding sensor 4 receives undesired light rays and lowers in rangefinding accuracy.
Furthermore, conversely, undesired light rays entering from the rangefinding lens portion 9b enters from the photometric lens portion 9a and reaches the photometric sensor 3 and accordingly the photometric sensor 3 lowers in photometric accuracy.
It is an object of the present invention to provide a measuring device whose measuring accuracy is prevented from lowering when a plurality of lenses for guiding light rays to each of a plurality of photoelectric converters are integrated for the purpose of reduction in size.
To attain the above object, in a first aspect of the present invention, there is provided a measuring device comprising a composite optical part including at least first and second photoelectric converters, and integrated first and second optical functional members that guide light rays to the first and second photoelectric converters, and a holding member that holds the first and second photoelectric converters and the composite optical part, wherein the first and second optical functional members of the composite optical part are coupled so as to restrain light rays entering one of the first and second optical functional members and exiting from the other one of the first and second optical functional members from entering one of the first and second photoelectric converters corresponding to the other optical functional member.
With the above construction according to the first aspect of the present invention, optical parts can be integrated without an optical path of light rays from the outside of ranges to be measured being formed, whereby the measuring device can be reduced in size without lowering in measuring accuracy.
Preferably, the first and second optical functional members are coupled in a fashion being offset in an optical axis direction of the measuring device.
Also preferably, the first and second optical functional members are different in focal length from each other.
More preferably, the first and second optical functional members have opposed surfaces formed due to the first and second optical functional members being coupled in a fashion being offset in the optical axis direction, and the opposed surfaces have been subjected to surface treatment.
Since the surface treatment is thus applied to the opposed end faces formed by the first and second optical functional members being coupled in a fashion being in the optical axis direction, formation of an optical path of light rays from the outside of the ranges to be measured can be more securely prevented. Preferably, the measuring device according to the first aspect comprises a semiconductor chip, and the first and second photoelectric converters are mounted on the semiconductor chip.
Since the first and second photoelectric converters are thus mounted on the same semiconductor chip, a measuring device that is further reduced in size can be realized.
To attain the above object, in a second aspect of the present invention, there is provided a measuring device comprising a pair of rangefinding sensors arranged at a predetermined distance from each other, a photoelectric converter disposed between the pair of rangefinding sensors, a composite optical part including a pair of rangefinding lens portions for guiding light rays to the pair of rangefinding sensors, and a predetermined optical functional member for guiding light rays to the photoelectric converter, the pair of rangefinding lens portions and the predetermined optical functional member being integrated together, and a holding member that holds the rangefinding sensors, the photoelectric converter, and the composite optical part, wherein the rangefinding lens portions and the optical functional member of the composite optical part are coupled so as to restrain light rays entering one of the rangefinding lens portions and the optical functional member and exiting from the other one of the rangefinding lens portions and the optical functional member from entering one of the rangefinding sensors and the photoelectric converter corresponding to the other one of the rangefinding lens portions or the optical functional member.
With the construction according to the second aspect of the present invention, optical parts can be integrated without an optical path from the outside of ranges to be measured being formed when a passive rangefinding device and another measuring device are integrated, whereby the measuring device can be reduced in size without lowering in measuring accuracy.
Preferably, the rangefinding lens portions and the optical functional members are coupled in a fashion being offset in an optical axis direction of the measuring device.
Also preferably, the rangefinding lens portions and the optical functional members are different in focal length from each other.
More preferably, the rangefinding lens portions and the optical functional members have opposed surfaces formed due to the rangefinding lens portions and the optical functional members being coupled in a fashion being offset in the optical axis direction, and the opposed surfaces have been subjected to surface treatment.
Since the surface treatment is applied to the opposed end faces formed due to the optical functional members being coupled in a fashion being offset in the optical axis direction, formation of an optical path of light rays from the outside of the ranges to be measured can be more securely prevented.
Preferably, the photoelectric converter comprises a remote control sensor.
As a result, a measuring device including a rangefinding device and a remote control device integrated together can be realized.
Preferably, the photoelectric converter comprises a photometric sensor.
As a result, a measuring device including a rangefinding device and a photometric device integrated together can be realized.
Preferably, the measuring device according to the second aspect comprises a semiconductor chip, and the pair of rangefinding sensors and the photoelectric converter are mounted on the semiconductor chip.
Since the pair of rangefinding sensors and the photoelectric converter are thus mounted on the same semiconductor chip, a measuring device which is further reduced in size can be realized.
The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.